Sweet Pea
2 of the 6 encyclopedias on this shelf carry an entry for Sweet Pea. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
a familiar garden annual plant belonging to the natural order Leguminosæ. It is a native of Sicily and other parts of the S. of Europe, and has been cultivated for its beautiful and fragrant flowers in American gardens for about 100 years. The varieties are very numerous, distinguished chiefly by the different shades of color of the flowers. It is so hardy that it may be sown in autumn and will not only withstand the cold of winter, but will bloom earlier and better than when sown in spring. Other species of Lathyrus are of interest either as ornamental plants or for food for man or cattle which they yield. The everlasting pea (L. latifolius) is an old favorite in flower gardens on account of its handsome but scentless flowers. The roots of L. tuberosus are eaten in Holland and other countries where it grows plentifully. The chickling vetch (L. sativus) is much used in Switzerland as fodder for cattle. The seeds ground into meal make palatable bread.
Aiton's Encyclopedia (1910)
a fragrant member of the pea family. The sweet pea is allied closely to the wild peas one finds climbing over bushes and along copse edges. It is distinctly a climber and needs cool, moist soil. Sweet peas should be planted early to get a start before hot weather comes on. They do best in a north and south row, in which case their roots are less exposed to the sun. The roots should be flooded with water of an evening. The leaves should not be sprinkled. There may be some dispute as to order, but sweet peas certainly merit a place in the first dozen flowers noted for delicate fragrance. For an account of the curious corolla, see PEA.
What Has Changed in the Last Century
The cultivation advice in both accounts still holds: Lathyrus odoratus is a Sicilian annual, autumn sowing does produce earlier bloom, and gardeners still argue about where it ranks among fragrant flowers. Two things have moved since. Between 1905 and 1908, while Collier's contributors were working, William Bateson and Reginald Punnett used sweet peas to find the first case of genetic linkage — flower colour and pollen shape refusing to assort independently — which made the plant a landmark in early genetics. And the chickling vetch (L. sativus), which Collier's in 1921 recommended as fodder whose seeds "ground into meal make palatable bread," is now known to contain the neurotoxin ODAP, identified in the 1960s as the cause of neurolathyrism, an irreversible paralysis seen where the crop is eaten heavily in famine years.
Written for this edition, 2026.